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Theorem infdifsn 9665
Description: Removing a singleton from an infinite set does not change the cardinality of the set. (Contributed by Mario Carneiro, 30-Apr-2015.) (Revised by Mario Carneiro, 16-May-2015.)
Assertion
Ref Expression
infdifsn (ω ≼ 𝐴 → (𝐴 ∖ {𝐵}) ≈ 𝐴)

Proof of Theorem infdifsn
Dummy variable 𝑓 is distinct from all other variables.
StepHypRef Expression
1 brdomi 8994 . . . 4 (ω ≼ 𝐴 → ∃𝑓 𝑓:ω–1-1→𝐴)
21adantr 486 . . 3 ((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) → ∃𝑓 𝑓:ω–1-1→𝐴)
3 reldom 8987 . . . . . . 7 Rel ≼
43brrelex2i 5708 . . . . . 6 (ω ≼ 𝐴 → 𝐴 ∈ V)
54ad2antrr 739 . . . . 5 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω–1-1→𝐴) → 𝐴 ∈ V)
6 simplr 781 . . . . 5 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω–1-1→𝐴) → 𝐵 ∈ 𝐴)
7 f1f 6783 . . . . . . 7 (𝑓:ω–1-1→𝐴 → 𝑓:ω⟶𝐴)
87adantl 487 . . . . . 6 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω–1-1→𝐴) → 𝑓:ω⟶𝐴)
9 peano1 7904 . . . . . 6 ∅ ∈ ω
10 ffvelcdm 7086 . . . . . 6 ((𝑓:ω⟶𝐴 ∧ ∅ ∈ ω) → (𝑓‘∅) ∈ 𝐴)
118, 9, 10sylancl 598 . . . . 5 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω–1-1→𝐴) → (𝑓‘∅) ∈ 𝐴)
12 difsnen 9086 . . . . 5 ((𝐴 ∈ V ∧ 𝐵 ∈ 𝐴 ∧ (𝑓‘∅) ∈ 𝐴) → (𝐴 ∖ {𝐵}) ≈ (𝐴 ∖ {(𝑓‘∅)}))
135, 6, 11, 12syl3anc 1398 . . . 4 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω–1-1→𝐴) → (𝐴 ∖ {𝐵}) ≈ (𝐴 ∖ {(𝑓‘∅)}))
14 vex 3454 . . . . . . . . . 10 𝑓 ∈ V
15 f1f1orn 6841 . . . . . . . . . . 11 (𝑓:ω–1-1→𝐴 → 𝑓:ω–1-1-onto→ran 𝑓)
1615adantl 487 . . . . . . . . . 10 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω–1-1→𝐴) → 𝑓:ω–1-1-onto→ran 𝑓)
17 f1oen3g 9001 . . . . . . . . . 10 ((𝑓 ∈ V ∧ 𝑓:ω–1-1-onto→ran 𝑓) → ω ≈ ran 𝑓)
1814, 16, 17sylancr 599 . . . . . . . . 9 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω–1-1→𝐴) → ω ≈ ran 𝑓)
1918ensymd 9040 . . . . . . . 8 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω–1-1→𝐴) → ran 𝑓 ≈ ω)
203brrelex1i 5707 . . . . . . . . . . 11 (ω ≼ 𝐴 → ω ∈ V)
2120ad2antrr 739 . . . . . . . . . 10 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω–1-1→𝐴) → ω ∈ V)
22 limom 7897 . . . . . . . . . . 11 Lim ω
2322limenpsi 9179 . . . . . . . . . 10 (ω ∈ V → ω ≈ (ω ∖ {∅}))
2421, 23syl 18 . . . . . . . . 9 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω–1-1→𝐴) → ω ≈ (ω ∖ {∅}))
2514resex 6020 . . . . . . . . . . 11 (𝑓 ↾ (ω ∖ {∅})) ∈ V
26 simpr 490 . . . . . . . . . . . 12 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω–1-1→𝐴) → 𝑓:ω–1-1→𝐴)
27 difss 4071 . . . . . . . . . . . 12 (ω ∖ {∅}) ⊆ ω
28 f1ores 6844 . . . . . . . . . . . 12 ((𝑓:ω–1-1→𝐴 ∧ (ω ∖ {∅}) ⊆ ω) → (𝑓 ↾ (ω ∖ {∅})):(ω ∖ {∅})–1-1-onto→(𝑓 “ (ω ∖ {∅})))
2926, 27, 28sylancl 598 . . . . . . . . . . 11 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω–1-1→𝐴) → (𝑓 ↾ (ω ∖ {∅})):(ω ∖ {∅})–1-1-onto→(𝑓 “ (ω ∖ {∅})))
30 f1oen3g 9001 . . . . . . . . . . 11 (((𝑓 ↾ (ω ∖ {∅})) ∈ V ∧ (𝑓 ↾ (ω ∖ {∅})):(ω ∖ {∅})–1-1-onto→(𝑓 “ (ω ∖ {∅}))) → (ω ∖ {∅}) ≈ (𝑓 “ (ω ∖ {∅})))
3125, 29, 30sylancr 599 . . . . . . . . . 10 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω–1-1→𝐴) → (ω ∖ {∅}) ≈ (𝑓 “ (ω ∖ {∅})))
32 f1orn 6840 . . . . . . . . . . . . 13 (𝑓:ω–1-1-onto→ran 𝑓 ↔ (𝑓 Fn ω ∧ Fun ◡𝑓))
3332simprbi 503 . . . . . . . . . . . 12 (𝑓:ω–1-1-onto→ran 𝑓 → Fun ◡𝑓)
34 imadif 6629 . . . . . . . . . . . 12 (Fun ◡𝑓 → (𝑓 “ (ω ∖ {∅})) = ((𝑓 “ ω) ∖ (𝑓 “ {∅})))
3516, 33, 343syl 19 . . . . . . . . . . 11 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω–1-1→𝐴) → (𝑓 “ (ω ∖ {∅})) = ((𝑓 “ ω) ∖ (𝑓 “ {∅})))
36 f1fn 6784 . . . . . . . . . . . . . 14 (𝑓:ω–1-1→𝐴 → 𝑓 Fn ω)
3736adantl 487 . . . . . . . . . . . . 13 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω–1-1→𝐴) → 𝑓 Fn ω)
38 fnima 6674 . . . . . . . . . . . . 13 (𝑓 Fn ω → (𝑓 “ ω) = ran 𝑓)
3937, 38syl 18 . . . . . . . . . . . 12 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω–1-1→𝐴) → (𝑓 “ ω) = ran 𝑓)
40 fnsnfv 6969 . . . . . . . . . . . . . 14 ((𝑓 Fn ω ∧ ∅ ∈ ω) → {(𝑓‘∅)} = (𝑓 “ {∅}))
4137, 9, 40sylancl 598 . . . . . . . . . . . . 13 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω–1-1→𝐴) → {(𝑓‘∅)} = (𝑓 “ {∅}))
4241eqcomd 2766 . . . . . . . . . . . 12 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω–1-1→𝐴) → (𝑓 “ {∅}) = {(𝑓‘∅)})
4339, 42difeq12d 4063 . . . . . . . . . . 11 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω–1-1→𝐴) → ((𝑓 “ ω) ∖ (𝑓 “ {∅})) = (ran 𝑓 ∖ {(𝑓‘∅)}))
4435, 43eqtrd 2795 . . . . . . . . . 10 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω–1-1→𝐴) → (𝑓 “ (ω ∖ {∅})) = (ran 𝑓 ∖ {(𝑓‘∅)}))
4531, 44breqtrd 5130 . . . . . . . . 9 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω–1-1→𝐴) → (ω ∖ {∅}) ≈ (ran 𝑓 ∖ {(𝑓‘∅)}))
46 entr 9041 . . . . . . . . 9 ((ω ≈ (ω ∖ {∅}) ∧ (ω ∖ {∅}) ≈ (ran 𝑓 ∖ {(𝑓‘∅)})) → ω ≈ (ran 𝑓 ∖ {(𝑓‘∅)}))
4724, 45, 46syl2anc 596 . . . . . . . 8 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω–1-1→𝐴) → ω ≈ (ran 𝑓 ∖ {(𝑓‘∅)}))
48 entr 9041 . . . . . . . 8 ((ran 𝑓 ≈ ω ∧ ω ≈ (ran 𝑓 ∖ {(𝑓‘∅)})) → ran 𝑓 ≈ (ran 𝑓 ∖ {(𝑓‘∅)}))
4919, 47, 48syl2anc 596 . . . . . . 7 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω–1-1→𝐴) → ran 𝑓 ≈ (ran 𝑓 ∖ {(𝑓‘∅)}))
50 difexg 5291 . . . . . . . 8 (𝐴 ∈ V → (𝐴 ∖ ran 𝑓) ∈ V)
51 enrefg 9019 . . . . . . . 8 ((𝐴 ∖ ran 𝑓) ∈ V → (𝐴 ∖ ran 𝑓) ≈ (𝐴 ∖ ran 𝑓))
525, 50, 513syl 19 . . . . . . 7 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω–1-1→𝐴) → (𝐴 ∖ ran 𝑓) ≈ (𝐴 ∖ ran 𝑓))
53 disjdif 4425 . . . . . . . 8 (ran 𝑓 ∩ (𝐴 ∖ ran 𝑓)) = ∅
5453a1i 11 . . . . . . 7 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω–1-1→𝐴) → (ran 𝑓 ∩ (𝐴 ∖ ran 𝑓)) = ∅)
55 difss 4071 . . . . . . . . . 10 (ran 𝑓 ∖ {(𝑓‘∅)}) ⊆ ran 𝑓
56 ssrin 4137 . . . . . . . . . 10 ((ran 𝑓 ∖ {(𝑓‘∅)}) ⊆ ran 𝑓 → ((ran 𝑓 ∖ {(𝑓‘∅)}) ∩ (𝐴 ∖ ran 𝑓)) ⊆ (ran 𝑓 ∩ (𝐴 ∖ ran 𝑓)))
5755, 56ax-mp 5 . . . . . . . . 9 ((ran 𝑓 ∖ {(𝑓‘∅)}) ∩ (𝐴 ∖ ran 𝑓)) ⊆ (ran 𝑓 ∩ (𝐴 ∖ ran 𝑓))
58 sseq0 4353 . . . . . . . . 9 ((((ran 𝑓 ∖ {(𝑓‘∅)}) ∩ (𝐴 ∖ ran 𝑓)) ⊆ (ran 𝑓 ∩ (𝐴 ∖ ran 𝑓)) ∧ (ran 𝑓 ∩ (𝐴 ∖ ran 𝑓)) = ∅) → ((ran 𝑓 ∖ {(𝑓‘∅)}) ∩ (𝐴 ∖ ran 𝑓)) = ∅)
5957, 53, 58mp2an 705 . . . . . . . 8 ((ran 𝑓 ∖ {(𝑓‘∅)}) ∩ (𝐴 ∖ ran 𝑓)) = ∅
6059a1i 11 . . . . . . 7 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω–1-1→𝐴) → ((ran 𝑓 ∖ {(𝑓‘∅)}) ∩ (𝐴 ∖ ran 𝑓)) = ∅)
61 unen 9081 . . . . . . 7 (((ran 𝑓 ≈ (ran 𝑓 ∖ {(𝑓‘∅)}) ∧ (𝐴 ∖ ran 𝑓) ≈ (𝐴 ∖ ran 𝑓)) ∧ ((ran 𝑓 ∩ (𝐴 ∖ ran 𝑓)) = ∅ ∧ ((ran 𝑓 ∖ {(𝑓‘∅)}) ∩ (𝐴 ∖ ran 𝑓)) = ∅)) → (ran 𝑓 ∪ (𝐴 ∖ ran 𝑓)) ≈ ((ran 𝑓 ∖ {(𝑓‘∅)}) ∪ (𝐴 ∖ ran 𝑓)))
6249, 52, 54, 60, 61syl22anc 852 . . . . . 6 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω–1-1→𝐴) → (ran 𝑓 ∪ (𝐴 ∖ ran 𝑓)) ≈ ((ran 𝑓 ∖ {(𝑓‘∅)}) ∪ (𝐴 ∖ ran 𝑓)))
638frnd 6723 . . . . . . 7 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω–1-1→𝐴) → ran 𝑓 ⊆ 𝐴)
64 undif 4437 . . . . . . 7 (ran 𝑓 ⊆ 𝐴 ↔ (ran 𝑓 ∪ (𝐴 ∖ ran 𝑓)) = 𝐴)
6563, 64sylib 221 . . . . . 6 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω–1-1→𝐴) → (ran 𝑓 ∪ (𝐴 ∖ ran 𝑓)) = 𝐴)
66 uncom 4156 . . . . . . 7 ((ran 𝑓 ∖ {(𝑓‘∅)}) ∪ (𝐴 ∖ ran 𝑓)) = ((𝐴 ∖ ran 𝑓) ∪ (ran 𝑓 ∖ {(𝑓‘∅)}))
67 eldifn 4067 . . . . . . . . . . 11 ((𝑓‘∅) ∈ (𝐴 ∖ ran 𝑓) → ¬ (𝑓‘∅) ∈ ran 𝑓)
68 fnfvelrn 7085 . . . . . . . . . . . 12 ((𝑓 Fn ω ∧ ∅ ∈ ω) → (𝑓‘∅) ∈ ran 𝑓)
6937, 9, 68sylancl 598 . . . . . . . . . . 11 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω–1-1→𝐴) → (𝑓‘∅) ∈ ran 𝑓)
7067, 69nsyl3 139 . . . . . . . . . 10 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω–1-1→𝐴) → ¬ (𝑓‘∅) ∈ (𝐴 ∖ ran 𝑓))
71 disjsn 4668 . . . . . . . . . 10 (((𝐴 ∖ ran 𝑓) ∩ {(𝑓‘∅)}) = ∅ ↔ ¬ (𝑓‘∅) ∈ (𝐴 ∖ ran 𝑓))
7270, 71sylibr 237 . . . . . . . . 9 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω–1-1→𝐴) → ((𝐴 ∖ ran 𝑓) ∩ {(𝑓‘∅)}) = ∅)
73 undif4 4419 . . . . . . . . 9 (((𝐴 ∖ ran 𝑓) ∩ {(𝑓‘∅)}) = ∅ → ((𝐴 ∖ ran 𝑓) ∪ (ran 𝑓 ∖ {(𝑓‘∅)})) = (((𝐴 ∖ ran 𝑓) ∪ ran 𝑓) ∖ {(𝑓‘∅)}))
7472, 73syl 18 . . . . . . . 8 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω–1-1→𝐴) → ((𝐴 ∖ ran 𝑓) ∪ (ran 𝑓 ∖ {(𝑓‘∅)})) = (((𝐴 ∖ ran 𝑓) ∪ ran 𝑓) ∖ {(𝑓‘∅)}))
75 uncom 4156 . . . . . . . . . 10 ((𝐴 ∖ ran 𝑓) ∪ ran 𝑓) = (ran 𝑓 ∪ (𝐴 ∖ ran 𝑓))
7675, 65eqtrid 2807 . . . . . . . . 9 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω–1-1→𝐴) → ((𝐴 ∖ ran 𝑓) ∪ ran 𝑓) = 𝐴)
7776difeq1d 4061 . . . . . . . 8 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω–1-1→𝐴) → (((𝐴 ∖ ran 𝑓) ∪ ran 𝑓) ∖ {(𝑓‘∅)}) = (𝐴 ∖ {(𝑓‘∅)}))
7874, 77eqtrd 2795 . . . . . . 7 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω–1-1→𝐴) → ((𝐴 ∖ ran 𝑓) ∪ (ran 𝑓 ∖ {(𝑓‘∅)})) = (𝐴 ∖ {(𝑓‘∅)}))
7966, 78eqtrid 2807 . . . . . 6 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω–1-1→𝐴) → ((ran 𝑓 ∖ {(𝑓‘∅)}) ∪ (𝐴 ∖ ran 𝑓)) = (𝐴 ∖ {(𝑓‘∅)}))
8062, 65, 793brtr3d 5135 . . . . 5 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω–1-1→𝐴) → 𝐴 ≈ (𝐴 ∖ {(𝑓‘∅)}))
8180ensymd 9040 . . . 4 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω–1-1→𝐴) → (𝐴 ∖ {(𝑓‘∅)}) ≈ 𝐴)
82 entr 9041 . . . 4 (((𝐴 ∖ {𝐵}) ≈ (𝐴 ∖ {(𝑓‘∅)}) ∧ (𝐴 ∖ {(𝑓‘∅)}) ≈ 𝐴) → (𝐴 ∖ {𝐵}) ≈ 𝐴)
8313, 81, 82syl2anc 596 . . 3 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω–1-1→𝐴) → (𝐴 ∖ {𝐵}) ≈ 𝐴)
842, 83exlimddv 1967 . 2 ((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) → (𝐴 ∖ {𝐵}) ≈ 𝐴)
85 difsn 4757 . . . 4 (¬ 𝐵 ∈ 𝐴 → (𝐴 ∖ {𝐵}) = 𝐴)
8685adantl 487 . . 3 ((ω ≼ 𝐴 ∧ ¬ 𝐵 ∈ 𝐴) → (𝐴 ∖ {𝐵}) = 𝐴)
87 enrefg 9019 . . . . 5 (𝐴 ∈ V → 𝐴 ≈ 𝐴)
884, 87syl 18 . . . 4 (ω ≼ 𝐴 → 𝐴 ≈ 𝐴)
8988adantr 486 . . 3 ((ω ≼ 𝐴 ∧ ¬ 𝐵 ∈ 𝐴) → 𝐴 ≈ 𝐴)
9086, 89eqbrtrd 5126 . 2 ((ω ≼ 𝐴 ∧ ¬ 𝐵 ∈ 𝐴) → (𝐴 ∖ {𝐵}) ≈ 𝐴)
9184, 90pm2.61dan 825 1 (ω ≼ 𝐴 → (𝐴 ∖ {𝐵}) ≈ 𝐴)
Colors of variables:    wff setvar class
This proof depends on syntax axioms:  ¬ wn 3   → wi 4   ∧ wa 401   = wceq 1569  ∃wex 1811   ∈ wcel 2144  Vcvv 3450   ⊆ wss 3896   ∖ cdif 4044   ∩ cin 4088   ∪ cun 4148  ∅c0 4277  {csn 4584   class class class wbr 5102  ◡ccnv 5650  ran crn 5652   ↾ cres 5653   “ cima 5654  Fun wfun 6537   Fn wfn 6538  ⟶wf 6539  –1-1→wf1 6540  –1-1-onto→wf1o 6542  ‘cfv 6543  ωcom 7881   ≈ cen 8978   ≼ cdom 8979
This proof depends on axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1827  ax-4 1841  ax-5 1942  ax-6 1999  ax-7 2040  ax-8 2146  ax-9 2154  ax-10 2177  ax-11 2193  ax-12 2212  ax-ext 2732  ax-sep 5248  ax-nul 5259  ax-pow 5327  ax-pr 5391  ax-un 7755
This proof depends on definitions:  df-bi 210  df-an 402  df-or 862  df-3or 1104  df-3an 1105  df-tru 1572  df-fal 1582  df-ex 1812  df-nf 1816  df-sb 2099  df-mo 2564  df-eu 2594  df-clab 2739  df-cleq 2752  df-clel 2835  df-nfc 2909  df-ne 2956  df-ral 3077  df-rex 3087  df-rab 3413  df-v 3452  df-sbc 3739  df-csb 3848  df-ss 3897  df-pss 4013  df-dif 4046  df-in 4090  df-un 4150  df-nul 4278  df-if 4482  df-pw 4558  df-sn 4585  df-pr 4587  df-op 4835  df-uni 4867  df-br 5103  df-opab 5167  df-mpt 5186  df-tr 5212  df-id 5546  df-eprel 5551  df-po 5559  df-so 5560  df-fr 5604  df-we 5606  df-xp 5657  df-rel 5658  df-cnv 5659  df-co 5660  df-dm 5661  df-rn 5662  df-res 5663  df-ima 5664  df-ord 6368  df-on 6369  df-lim 6370  df-suc 6371  df-iota 6497  df-fun 6545  df-fn 6546  df-f 6547  df-f1 6548  df-fo 6549  df-f1o 6550  df-fv 6551  df-om 7882  df-er 8725  df-en 8982  df-dom 8983
This theorem is used by:  infdiffi  9666  infdju1  10275  infpss  10301  soinfdom  35774
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